Reed for a reed relay



June 28, 1966 J, scHEEPs'n-RA ET AL 3,258,557

REED FOR A REED RELAY Filed Aug. 28, 1964 A f: Wwf/1M United States Patent C) 3,258,557 REED FOR A REED RELAY .lan Scheepstra, Tjakko Marinus Schuringa, and Willem Frederik Bosman, Hilversum, Netherlands, assignors to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Filed Aug. 28, 1964, Ser. No. 392,757 Claims priority, application Netherlands, Sept. 4, 1963, 297,517 13 Claims. (Cl. Zlio-87) The invention relates to an improved reed for a reed relay and in particular a flexible reed with improved bounce or chatter characteristics,

Reed relays are known in a variety of designs as lndicated in German Patent Numbers 1,086,327 (January 1961), 1,104,024 (opened April 1961), 1,111,292 (opened July 1961) and 1,117,761 (opened November 1961). In each case one reed of two or more reeds within the envelope is made relatively flexible and therefore moveable into engagement with another reed to provide a closed contact.

The known reed relays, exhibit an unfavorable characteristic refererd to as chatter or bounce, i.e. when the deflected reed impacts with a counter reed, the deflected reed vibrates for a period of time and the contact may be opened momentarily or the reed may sepanate and the Contact remains open until the reed is deflected a second time. Y

Obviously unreliable operation is a serious disadvantage.

It is the object of this invention to overcome the disadvantage above noted in an ellicient and economic manner.

In brief, the improvement according to the invention comprises providing a reed with flexible portions which minimizes the tendency of the contact portions of the reeds to separate during the period of vibration immediately following closure of the reed contact.

The first embodiment of the invention, hereinafter described, relates to a known reed which is modified in accordance with the teaching of the invention.

The second embodiment of the invention relates to a reed having a novel construction in accordance with the teaching of the invention.

The above and other features, objects and advantages of the present invention will be fully understood from the following description considered in connection with the accompanying illustrative drawings.

FIG. 1 shows a longitudinal `section of one embodiment of a relay according to the invention having two identical flexible tongues, which when brought together form a make-contact.

FIG. 2 is a plan view of one of the flexible tongues of the relay of FIG. 1;

FIG. 3 shows a portion of a longitudinal section of a second embodiment of a relay according to the invention,

FIG. 4 is a plan view of one of the flexible tongues of this relay shown in FIG. 3.

It is to be noted that movement of a flexible reed lies in the plane of the drawing in FIGS. 1 and 3 and is thus Iat right angles to this plane in FIGS. 2 and 4. It is also to be noted that several dimensions illustrated in the drawing are not shown in their correct proportions, but numerical examples are given for certain dimensions where such may be important in the description following hereinafter.

The relay shown in FIGS. l and 2 comprises a closed tubular glass envelope 1 having llexible magnetic reeds 2 and 3 sealed into the opposite ends of the glass tube.

ICC

Each reed consists of a nickel iron wire which is initially circular, having a diameter of, for example, approximately 1.3 mms. This wire is locally flattened to .a greater or lesser extent as described hereinafter. An undeformed portion of each reed extends through an end of the envelope 1 defining a fulcrum f for the cantilevered portion located inside the envelope which is llattened over substantially its full length to a thickness of approximately 0.6 mm., so as to form flexible portions 4 .and 5 and the contact areas 6 and 7 of the same thickness. The contacts are at the overlapping ends of the tongues. The deformed portion of each reed has a length of approximately 20 mms., whereas the length of the contact areas 6 and 7 is equal to or a little greater than the overlap of the two reeds which in this example is approximately 1.0 mm. Each of the contact areas 6 and 7 may be covered with a thin surface layer of a metal having good electric contact properties, for example, gold or rhodium.

The reeds 2 and 3 have additionally llattened portions 8 and 9 or small length adjacent the contact areas 6 and 7 providing a hinge for the contract portions 6 and 7. The said portions 8 and 9 are obtained by pressing two prismatic or cylindrical bodies from opposing sides into the reeds after they had been uniformly llattened over the illustrated length for forming the portions 4, 6 and 5, 7 respectively. The indentations 8 and 9 are preferably made with circular-cylindrical shaped dies having their axes at right angles to the plane of the drawing of FIG. l (parallel to the plane of reeds 4 and 5). In this example, small cylinders having a radius of lapproximately 5 mms. have been pressed into the material of the reeds so that the minimum thickness of the deformations 8 and 9 is approximately 0.4 mm. Although the thicknessand hence the moment of inertia of the section--of the portions 8 and 9 is smaller than that of the portions 4 and 5, it is substantially the last-mentioned portions 4 and 5 which determine the flexibility of a reed. This is due to their greater length as well as their position with respect to the fixed end of the reed. Consequently, upon llexure of a reed 2 or 3, upon energizing the coil 10, the displacement of the relevant contact area will be determined substantially by the llexure of the relevant portion 4 or 5. Thus, reeds are moving towards each other until the free end of the reeds, the contact areas 6 and 7 abut against one another. The closure movement of the contact areas will be little influenced by the flexibility of the portions 8 and 9 up to the moment the said contact areas engage each other. After the two contact areas engage, however, the flexibility of the portions 8 and 9 is important since they now determine the succeeding movement of the portions 4 and 5 which will have a certain kinetic energy. By means of the llexibility of the portions 8 and 9, the contact between the contact .areas 6 and 7 is not interrupted by the swinging or wave motions set up in the reeds or its portions 4 and 5 which follows engagement of the contacts 6 and '7. Presumably the flexibility of portions 8, 9 allows a certain motion at the ends of the portions 4 and 5 a direction of movement which somehow dampens or diminishes bounce or chatter which separates the reeds because the magnetic attraction drawing the reeds together is exceeded. This movement of the portions 4 and 5 which adjoin the more reduced or flattened portions 8 and 9 may be greater as the bending stillness of the portions 8 and 9 is reduced. An unduly small bending stiffness of portions 8 and 9 results, however, in irregular movement of the contact areas 6 and 7 upon energization of the reeds which is due to flexing of the portions 8 and 9 respectively, i.e., flexing at 8 and 9 before the contact areas meet.

The magnetic reed relay shown in FIGS. 3 and 4 likewise has two identical lflexible reeds 32 and 33 which are `sealed in opposing portions of a glas-s envelope and which overlap at their ends forming contact areas 34 `and 35. Each of the reeds are formed of a piece of circular nickel-iron wire, of approximately 0.55 mm. diameter, has within the envelope 30, two flexible portions 36 and 37, obtained by deformation of the wire, whereby it has been flattened more or less by `means of pressure from each side. The tirst flexible portion 36, which is located near the envelope or fulcrum point seal of the reeds is attened to a thickness of approximately 0.15 mm. and has a length of approximately 2.5 mms. The second liexible portion 37, which directly adjoins the contact areas 34 and 35 respectively, is approximately 0.2 mm. thick and approximately 1.2 mms. long. The two said liexible portions are connected together by means of a portion 8, which is undeformed and hence circular and which also has a length of 2.5 mms. The total length of the reeds 32 Iand 33 respectively within the envelope 30, reckoned from the beginning of the portion 36, is approximately 7 mms. Due to the undeformed portion 38, the manufacture of the reed, when starting from wire-shaped or rod-shaped material, is easier than in the case where the reed is obtained by Adeformation of the full length situated within the envelope. The desired deformation of the initial material is obtained by compressing it between two dies each of a length -at least equal to the length of the portion of the reed to be accommodated inside the envelope. Since the portion of the wire which corresponds to the undeformed Iportion 3S of the reed to be obtained is not deformed and hence each die at the area of this portion must have a cavity which is matched to the initial diameter of the initial material, for, as the dies move towards each other they cannot `be allowed to shift relative to one another as the result of the material of the wire being caused to flow in a lateral direction 4at the area of the deformation if the reed is to acquire the shape desired.

Likewise, contact areas 34 and 35 are obtained by yslightly flattening the initial material of the reed. However, the flattening of these ends of the tongue is not as great `as that of the flexible portions 36 and 37. The contact areas 34 and 35 are, for example, 0.32 mm. thick and therefore considerably more rigid than the iiexible portions 36 Iand 37. However, the contact areas 34 and are flattened to provide the desired magnetic attraction between the ends of the reeds and also provide a sufiiciently large electric contact area.

The examples above described relate to relays having two identi-cal co-acting reeds both of which are flexible. However, Ia relay according to the invention can be equipped with only one flexible reed as described above which ico-acts with a reed which is not deformed except for the contact area at its free end and which is thus rigid or at least relatively inliexible.

Also a flexible reed according to the invention as above described may alternately co-act in known manner with two other reeds (change over contact) preferably by using magnetic prepolarizfation for one or more of the reeds. In this case, one reed or both of the other reeds may be formed in the same manner as described above and hence be flexible; the other two reeds can be undeformed except for the :contact area, and hence be substantially rigid.

While we have shown and described the preferred embodiment of our invention, it will be understood that the l-atter may be embodied otherwise than as herein specifically illustrated 4or described and that in the illustrated embodiment certain changes in the details of construction Iand in the arrangement of parts may be made without departing from the underlying idea or principle of the invention within the scope of the appended claims.

What is claimed is:

1. An improved reed for a magnetic reed relay comprising a wire of given diameter, said wire having a laterally flattened portion in which the thickness of said flattened portion is less than said diameter, saidportion being located 'adjacent the fulcrum of said reed for locally increasing the flexibility of said reed in la plane normal to said flattened portion, a contact area at one end, and a second laterally attened section adjacent said contact area for locally flexibly hinging said contact area at the end of said reed.

2. An improved reed according to claim 1 wherein said wire is undeformed between said liattened portion and said flattened section.

3. An improved -reed according to claim 1 wherein said flattened portion is of a substantially uniform thickness extending from said second laterally liattened section to a point adjacent the fulcrum of said reed and said second flattened section is of less thickness than said flattened portion.

4. An improved reed according to claim 3 wherein the length of said attened section -is not appreciably greater than one lifth the length of said reed measured from said fulcrum to the end thereof defining said contact area.

5. An improved reed according to claim 4 wherein said wire has ya diameter on the order of 1.3 millimeters, said liattened portion has a length on the order of 20 millimeters, and a thickness on the order of 0.6 millimeter, and said attened section has a thickness on the order of 0.4 millimeter and a length on the order of 0.5 millimeter.

6. An improved reed according to claim 5 in combination with a hollow glass cylinder closed at e-ach end, said fulcrum being located adjacent said one said closed end within said cylinder Iand a -counter reed within said envelope having a contact surface corresponding with said cont-act area of said reed and normally spaced therefrom, and means for moving said reed for engaging said contact area with the contact surface of said counter reed.

7. An improved reed -relay comprising an elongated hollow envelope member having a reed sealed in each of the opposite ends of said envelope and overlapping in spaced relation within the hollow of said envelope, each said reed comprising a wire having a contact area at the overlapped ends thereof within said envelope, at least one of said reeds having .a laterally attened portion of reduced thickness for locally increasing the flexibility of `said reed in -a plane normal to said flattened portion, and a second laterally liattened section adjacent the associated contact area for locally liexibly hinging said contact area at the end yof said reed.

8. An improved reed relay according to claim 7 wherein the flattened portion of said one reed is separated from said flattened section thereof by an -undeformed portion of said wire.

9. An improved reed relay according to claim 8 wherein said wire has a diameter on the order of 0.55 millimeter and va length on the order of 7 millimeters, said attened portion has la thickness on the order of 0.15 millimeter and -a length on the order of 2.5 millimeters, said undeformed portion has a length approximately equal to the length of said flattened portion, and said ilattened section has a thickness on the order of 0.2 millimeter and a length on the order of 1.2 millimeters.

10. An improved reed relay according to claim 7 wherein the flattened portion of said one reed is of a substantially uniform thickness extending the length of said reed within said envelope and said second attened section form a depression in said liattened portion.

11. An improved reed relay according to claim 10 wherein the attened .section of said one reed is not appreciably greater than one-fifth the length of said reed confined within said envelope.

12. An improved reed relay .according to claim 10 wherein said wire has a diameter on the order of 1.3 millimeters, said flattened portion having `a length on the order of 20 millimeters and a thickness on the order of 0.6 millimeter, said flattened section having a thickness on the order of 0.4 millimeter and a length on the order of 0.5 millimeter.

5 6 13. An improved reed relay according to claim 7 where- References Cited by the Examiner in said w'ireha's a diameter not .substantially less than UNITED STATES PATENTS 0.55 milllmeter and not substant1ally greater than 1.3 millimeters, said attened portion has a thickness not 1,697,872 1/1929 Johns@ 29-155 substantially less than 0.15 millimeter Iand not substan- 5 31059074 10/1962 Dal Blanco et 'al- --e- 20o-87 tially greater than 0.6 millimeter, and a length not sub- 3087125 4/1963 Scholeeld 200"87 stantially'less than 2.5 millimeters and not substantially greater than 20 millimeters, and said flattened section has BENJAMIN DOBECK, Plmm'y Exflmmefa thickness not substantially less than 0.2 millimeter and not substantially greater than 0.4 millimeter and a length 10 BERNARD A' GILHEANY Exammer' on the -order of 1 millimeter. J. I. BAKER, Assistant Examiner. 

1. AN IMPROVED REED FOR A MAGNETIC REED RELAY COMPRISING A WIRE OF GIVEN DIAMETER, SAID WIRE HAVING A LATERALLY FLATTENED PORTION IN WHICH THE THICKNESS OF SAID FLATTENED PORTION IS LESS THAN SAID DIAMETER, SAID PORTION BEING LOCATED ADJACENT THE FULCRUM OF SAID REED FOR LOCALLY INCREASING THE FLEXIBILTY OF SAID REED IN A PLANE NORMAL TO SAID FLATTENED PORTION, A CONTACT AREA AT ONE END, AND A SECOND LATERALLY FLATTENED SECTION ADJACENT SAID CONTACT AREA FOR LOCALLY FLEXIBILITY HINGING SAID CONTACT AREA AT THE END OF SAID REED. 